Property, Plant & Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 27, 2019
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 1,072,322	$ 1,018,029
Less: accumulated depreciation	(537,941)	(476,066)
Property, Plant And Equipment, Net	534,381	541,963
Depreciation	66,400	61,400	$ 55,500
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	42,041	41,955
Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	284,146	283,617
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	88,549	83,764
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	128,008	126,942
Computer Systems and Software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	258,981	230,800
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	33,565	31,845
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	22,923	19,545
Leased Equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 214,109	$ 199,561